Interceptor that validates the contents of WebServiceMessages using a schema. Allows for both W3C XML
and RELAX NG schemas.

When the payload is invalid, this interceptor stops processing of the interceptor chain. Additionally, if the message
is a SOAP request message, a SOAP Fault is created as reply. Invalid SOAP responses do not result in a fault.

The schema to validate against is set with the schema property or schemas property. By
default, only the request message is validated, but this behaviour can be changed using the
validateRequest and validateResponse properties. Responses that contains faults are not
validated.